Muffler



C. HOLLERITH MUFFLER Filed Oct. 12, 193e C'HARLES LL/ LEH/TH March 21, 1939.

Patented Mar. 2.1,' 1939 UNiTED STATES PATENT OFFICE Hayes Industries, Inc., Jackson, Mich., a corporation 'of Michigan Application october 12, 193s, serial No. 105,224

17 claims.

This invention relates to apparatus for attenuating sound waves and more particularly to mufflers for the exhaust gases of internal combustion engines of vehicles. n

Such apparatus as heretofore constructed` has been of a design insertable into the exhaust conduit with the weight of the muffler construction supported from the sections on the exhaust pipe entirely from the heads of the outer shell of the muiller. In other words the interior construction of the muler possessing the sound wave attenuating characteristics was in no sense a continuation of the exhaust conduit with reference to distribue tion of the stresses set up within the muiiier itself and the weight of the muiiler construction.

The apparatus of the present invention has for its object to bring intoeifect a redistribution of the stresses set up within the mufiler due to heat and resulting expansion and due to the weight of the muiller construction when compared with prior practices and results in removal for the most part of such stresses from the shell of the exterior construction of the muffler.

Another object is to provide a muffler construction of the type described which may be easily assembled and in which the inner construction of the muier becomes more of a part of the exhaust conduit and thus a more suitable arrangement for use in connection with internal combustion engines having resilient or floating mountings.

A further object resides in novel muffler construction possessing satisfactoryy sound wave attenuating characteristics and in addition embodying the above mentioned structural advantages.

Other objects including improvements in construction for permitting expansion and for eliminating shell noises will be more fully treated hereinafter.

These and other objects will be apparent from the following description when taken with the accompanying drawing in which, Fig. 1 is a section on the line I-I of Fig. 2, and

Fig. 2 is a vertical section through approximately the center of the muiller.

Referring particularly to the drawing reference character I indicates a shell which is preferably of double wall construction as would be produced by telescoping two sheet metal tubes or rolling a sheet metal strip into a double layer coil. Within the shell I is disposed sound attenuating structure built up from sheet metal sections which are spot welded together at points indicated by the reference character 2. In each end of the shell I are heads 3 and 4 each having a suitable opening for the reception'of the inlet and outlet connectors 5 and 6. The head 3 of the shell I is welded to the connector 5 to locate the position of the shell with reference to the interior muiiler structure upon which the shell is supported. At its inner end the connector 5 is provided with a belled end 6. A

(Cl. ISL-54) tube 1 is connected at one end to theybelled end 6 and has the other end partially sealed by a bushing plate 8. The bushing plate 8 has an eccentrically disposed reduced opening surrounded by an axially extending flange 9 to which is connected a tube I0. 1t will be observed from Fig. l that the tube I0 is of somewhat less diameter than the inlet connector 5 and has its end adjacent the inlet connector 5 belled into sliding engagement therewith. Also it will be observed that the tube l0 extends axially within the tube 1 but eccentrically with respect to the longitudinal axis thereof. A baille plate I5 is secured to the tube IU somewhat nearer the belled end 6 than the bushing plate 8 of the tube 1 and defines with the tube 1 resonating chambers I6 and I1. Communication is established between the interior of the tube III and the resonating chamber I6 by a plurality of perforations I8 `and between the interior of the tube II) and the resonating chamber I1 by a plurality of perforations I9. The resonating chamber I6 is somewhat smaller than the resonating chamber I1 and is for attenuating relatively high frequency tones. The baille plate I5 is in sliding contact with the tube 1 so that any unequal expansion between the tube 1 and the tube II) will be compensated for, not only by the sliding fit of the baille plate I5 but also by the sliding fit of the belled end of the tube I0 with the inlet connector 5. The head2 is secured to the interior muliler structure in the manner of the head 3 just described. An outlet connector 20 to which is attached the head 4 has a belled end 2| disposed within the shell I. Connected to the belled end 2 I. is a tube 22 projecting into the shell I and'into overlapping and contacting relation with the tube 1. A bushing plate 23 is securedin the inner end of the tube 22 and has therein an eccentrically disposed opening defined by an axially extending ange 29. A tube 30 extending throughout the length of the shell 22 is secured at one end to the flange 29 and is slidably disposed at the other end within the outlet connector 20. A baffle plate 35 is fixed to the tube 30 and extends radially into contacting and sliding engagement with the tube 22, forming with the tube 22 resonatingchambers 36 and 31. The resonating chamber 36 near the outlet end is materially smaller than the resonating chamber 31 and is for the purpose lof the attenuating high frequency tones. Communication between the tube 30 and the resonating chamber 36 is established by a plurality of perforations 38 and between the tube 30 and the chamber 31 by a plurality of perforations 39.

As shown particularly in Fig. 2, the tubes 1 and 22 throughout their overlapping length are in Contact with each other and are spot Welded together. Also, it. will be observed from Fig. 2 that the tubes 1 and 22 are disposed eccentrically with respect to or to one side of the shell l.

position and welding the same This arrangement may be varied to bring the outlet and the inlet connectors in any desired position depending upon the exhaust conduit locations. 'I'he tube 1 is provided with a plurality of perforations 40 in the portion thereof defining the resonating chamber I1, and the tube 22 is provided with a plurality of perforations 3l in the portion thereof dening the resonating chamber 31. The perforations 40 and 4I establish communication -between the resonating chambers I1 and 31.

A baille plate 42 disposed transversely in` the shell I is secured to the shell I establishing a resonating chamber 43 at the outlet end of the shell I. An opening 44 in the baffle plate 42 genend of the tube I between the resonatit will be understood that the structural departure presented by the present invention lends itself very well to the present accepted theory of eifective acoustical circuits.

ing connection between the baille plate 42 and the tube 22 permits relative movement if there be unequal expansion of the shell I and the shell 22.

. Also the sliding connections between the tube 30 and the outlet connector 20, and baille plate 35 and the tube. 22 permit a relative movement if there be unequal expansion between the tube 22 and the tube 30.

The present construction effects a substantial departure from heretofore known muiiiers in that being supported through the-shell as has been the practice. That is to say, in the illustrated form o1' the invention the tubes 1 and 22 which are rigidly united in their overlapping relation, together with the connectors and 20, constitute an integral structure which becomes a part of the exhaust conduit in which it is inserted. The shell I with its headers 3 and 4 and baille 42 are in effect hung from this integral interior structure of the muilier.

In production the associated connectors serted into the shell I and through the baille 42. The fabrication of the muiiler construction is then completed by placing the heads J and 4 in to the shell I and the connectors 5 and 20. By having the integral interior structure slidably in the baille 42 as well as havingthe tubes I Il and 30 anchored only at one point and slidably supported throughout the remainder of their lengths, stresses-and distortion from expansion are materially lessened.

and the major portion of the ex-l Moreover, by redistributing the stresses formerly carried for the most part by the shell and especially the heads thereof, the period of serviceability of the shell is materially lengthened. The advantages the present construction offers in yield to the engine torque will be apparent to those skilled in the art.

Having thus described my invention what I desire to secure by Letters Patent and claim is:

1. In a muilier construction adapted to be inserted in an exhaust conduit of an internal combustion engine, a relatively rigid interior muiiling construction defined by spaced nested tubes constituting resonator chambers and having inlet and outlet connectors rigidly supported therefrom, and

thereof suspended from one end of said outer shell.

2. A muffler of the retroverted gas iiow type comprising a pair of interior muflling structures having nested inner and outer tubes in spaced relation to form acoustical chambers disposed in overlapping relation with said outer tubes integrally united with each other, said inner tubes deiining central straight through passages in said mutliing structures, inlet and outlet connectors rigidly connected to said muilling strucinterior structures.

3. In a muiiler construction of the type disclosed, a pair of interior muilling structures cornprising perforated straight through central conduits. means embracing said conduits dening interior structures, said interior structures being suspended with respect to said exterior shell.

4. In a muiller construction, a plurality of nested tubes collectively dening a gas conduit and a resonator chamber, means acoustically connecting said conduit and chamber, means spaced longitudinally of said tubes for positioning the same in spaced relation. certain of said last means integrally connecting said tubes, certain other 5. In a muilier construction, an elongated shell, headers having openings therein disposed at opposite ends of said shell for enclosing the same, inlet and outlet connectors having enlarged inner ends positioned in said openings of said heads,

a pair of tubes integrally connected to the enlarged ends of said connectors disposed longitudinally with. the interior of said shell in juxtaposition with the exterior surfaces of each other integrally connected, tubes supported in spaced relation within said ilrst tubes and communicating with said connectors to provide straight frequency filter chambers being freely suspended throughout the major portion of their lengths from said outer shell, and means defining resonator chambers of substantially `greater volume than said high frequency chambers acoustically connected with said conduit sections intermediate said high frequency chambers.

'1. In a muiller construction, an outer shell of double wall metal to metal construction, means defining an inlet and an outlet for the exhaust gases, and means defining high frequency filter chambers acoustically connected with said inlet and outlet disposed directly adjacent thereto within said shell.

8. In a mulller construction of the type described, an outer shell, an inlet conduit, a perforated elongated tube axially aligned with said' inlet and positioned Within said shell, the inner end of said perforated tube opening directly into the interior of said shell, a baffle within said shell dividing the interior thereof into a plurality of resonator chambers directly-acoustically connected, an outlet associated with said shell, a perforated conduit aligned with said outlet and having its inner end opening directly .into the interior of said shell, the inner ends of said perforated conduits opening into the same resonator chamber defined within said shell and communicating with each other therethrough, and tubes embracing said perforated conduit section and defining therewith resonator chambers.

9. A muiller construction of the type described comprising inlet and outlet connectors, interior mullling structures with which said connectors coact, said interior muiilng structures being in overlapped relation and Welded to each other tol form a rigid construction and a shell laterally spaced from' and embracing said interior muiiling structures, said interior structures being suspended with respect to said exterior shell.

10. A muiller to be inserted in the exhaust conduit of an automobile characterized by the fact that the outer shell is materially relieved of supporting and operating stresses, comprising inner shells operatively connected together, connectors for the mumer to manifold and tail pipe sections of the exhaust conduit having enlarged head portions rigidly attached at the ends of said inner `shells to form therewith a structural unit within and through the outer shell, and an outer shell embracing said inner shells and through which said connectors extend, said outer shell being supported from said structural unit, r

11. A muiller as set forth in claim 10 in which said inner shells are in direct contact with each other." A

12. A muiiier comprising an inner shell, a gas conduit located within said inner shell and spaced therefrom to form an acoustical chamber, said conduit and inner shell being eccentrically disposed to one another, means acoustically connect-- ing the interior or said conduit and the interior of said' inner shell, an outer shell embracing said inner shell and a connector extending through said outer shell and in axial alignment with said gas conduit.

13. A mutller comprising a pair of inner shells rigidly secured to each other to form an, interior structural unit, gas conduits located within said inner shells and spaced therefrom to provide acoustical chambers, connectors in axial align to end portions of said inner shells, and an outer casing. embracing said inner shells.

14. A muffler of a modified straight through type, comprising .an outer casing, a pair of inner shells of substantially less length than said outer casing with portions thereof in overlapping and direct contact with each other, one of said inner shells being shorter than the other, means rigidly connecting said inner shells to form an interior structural unit for the outer shell of the muiller and an outer shell embracing said inner shells, said inner shells being cantilevered with respect to said outer casing.

15. A muilier comprising an inlet connector having an enlarged'head, an inner shell, said head being rigidly connected with said shell, an outlet connector having an enlarged head, a second inner shell rigidly connected with said second head, means rigidly connecting said shells, and an outer shell enclosing said inner shells and through which said connectors pass.

16. A muffler to be inserted in an exhaust conduit of automobiles and characterized by the fact that it is materially relieved of supporting and operating stresses, comprising a structural unit located Within and extending through the outer shell including inlet and outlet connectors, inner shells to which said connectors are integrally and rigidly attached, said inner shells being in juxtaposition and integrally and directly attached to each other, and an outer shell, embracing but laterally spaced from said inner shell, said inner shells being substantially suspended from said outer shell, whereby the supporting and operating structures are directly carried through the walls of said connectors and inner shells.

11. In a muffler construction of the type disclosed, a pair of interior mufiiing structures comprising perforated straight through central conduits, means embracing said conduits dening resonator chambers, the exterior surface of said muiiling 'structures being disposed side by side in direct contact and being integrally connected to each other, inlet and outlet connectors constituting continuations of said central conduits, and an exterior shell housing said muiiling construction and embracing sections of said connectors projecting outwardly through said shell, said exterior shell being laterally spaced from said interior structures, one of said interior structures being cantilevered with respect to said exterior shell, from one of said connectors.

.CHARLES HoLLrrarrH.

` CERTIFICATE OF CORRECTION.

Patent No. 2,151,LL7O. March 2l, 1959.

l CHARLES HOLLERITH.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: .Page 5, first column, line 5, claim 5,- for "with" read within; and that the said Letters Patent should be read with this correction therein `that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 9th day of May, A'. D. 1959.

Henry Van Arsdale (Seal) Acting Commissioner of Patents. 

